Novel copolymaides of phenylindan carboxylic acid



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ABSTRACT UP THE DISCLGSURE Copolyamides having high boiling water shrinkage are composed of hexamethylene adipamide and hexamethylene 3-(4-carboxyphenyl)1,1,3-trimethyl-5-indan carboxylamide. These copolyamides are useful in the production of yarns, fabrics, films, textile fibers and reinforcing cords.

Polyamides, such as polyhexamethylene adipamide (nylon 66) and polycaproamide (nylon 6) are Well known in the art and have found significant commercial success both as textile fibers and as reinforcing fibers, such as tire cord. Although the textile fibers obtained from the previously known fiber-forming polyamides heretofore known are of great value, much research effort is being continuously expended in order to improve their properties. For example, these previously known polyamides all possess a relatively low shrinkage value, that is, the amount of shrinkage that occurs in fibers made from these polyamides when they are treated with boiling Water is relatively small. In some commercial uses, for example, as hosiery, it is desirable that the polyarnide textile fibers have increased shrinkage. Furthermore, in the production of conjugate fibers, that is, a fiber having two or more components, it is extremely desirable that at least one of the components have a relatively high boiling water shrinkage. This is necessary in order that the crimp in a conjugate fiber be significant and permanent.

While, as pointed out above, previously known polyamides have found significant use in the reinforcement of rubber articles such as vehicle tires, an inherent drawback in their use to reinforce vehicle tires is their tendency to fiatspot. Flatspotting is a term used to describe the outof-roundness that occurs when a polyamide reinforced vehicle tire is allowed to rest for a period of time. That portion of the tire which is in contact with the pavement becomes flattened and, when the vehicle is started again this fiat spot causes vibration of the vehicle. While this phenomena of fiatspotting is not completely understood, there is at present a great deal of effort being put into finding a solution of this problem as regards polyamide tire cords.

It is an object of this invention to provide a novel polyamide.

I t is a further object of this invention to provide a novel synthetic linear fiber-forming copolyamide which has increased boiling water shrinkage characteristics.

It is a further object of this invention to provide a novel synthetic linear copolyamide from a phenylindan dicarboxylic acid.

It is a still further object of this invention to provide a copolyamide from a phenylindan dicarboxylic acid which shows a reduced tendency to fiatspot when used as a reinforcing fiber in rubber vehicle tires.

It is a still further object of this invention to provide a textile fiber composed of this novel synthetic linear fiberforming copolyamide.

It is a still further object of this invention to provide a process for produciru a novel synthetic linear fiberforming copolyamide.

These and other objects will become apperent from the description given hereinafter.

States Patent 0 "ice The copolyamides of the present invention are useful in the production of shaped articles by extrusion, rnolding or casting in the nature of yarns, fabrics, films, pellicles, bearings, ornaments or the like. They are particularly useful in the production of textile fibers and as reinforcin cords produced therefrom.

The present invention provides a novel linear fiberforming copolyamide composed of (A) 1 to 99 mole percent, based on the molecular weight of the copolyamide, of units represented by the structure -L I(OHZ)GI I-( ;(CHQ)4 (B) 1 to 99 mole percent, based on the molecular weight of the copolyamide, of units represented by the structure wherein R is a divalent hydrocarbon radical selected from the group consisting of tetramethylene and 1,4-Cyclohexylene and R is a member of the group consisting of hydrogen and alkyl groups containing 1 to 3 carbon atoms.

In a typical preparation the copolyamide is formed by interpolymerizing (A) substantially equimolecular proportions of adipic acid and hexamethylene diamine, (B) substantiaily equimolecular proportions of a phenylindan dicarboxylic acid and a diamine selected from the group consisting of hexamethylene diamine and 1,4-cyclohexanbis-(methylamine), wherein component (A) is present in an amount sutficient to provide 1 to 99, preferably 50 to mole percent of the final copolymer and component (B) is present in an amount sufiicient to provide 1 to 99, preferably 10 to 50 mole percent of the final copolymer. It will be understood that the designation equimolecular proportions of the diamines and the diacids includes the preformed salt reaction products thereof. It is of course obvious that the total mole percentage will not exceed 100 mole percent.

The copolyamides of this invention are prepared by procedures well known in the art and commonly employed in the manufacture of simple polyamides. That is, the reactants are heated at a temperature of from C. to 300 C. and preferably from 200 C. to 295 C. until the product has a sufiiciently high molecular weight to exhibit fiber-forming properties, which properties are reached when the copolyamide has an intrinsic viscosity of at least 0.4. The reaction can be conducted at super atmospheric, atmospheric, or subatmospheric pressure. Often it is desirable, especially in the last stage of the reaction, to employ conditions, e.g. reduced pressure, which will aid in the removal of the reaction by-products. Preferably the reaction is carried out in the absence of oxygen, for example, in an atmosphere of nitrogen.

Intrinsic viscosity as employed herein is defined as in which N is the relative viscosity of a dilute solution of the polymer in rn-cresol in the same units at the same temperature and C is the concentration of grams of polymer per 100 cc. of solution.

The amount of component (A) present in the copolymers of the present invention ranges from 1 to 99, preferably 90 to 50 mole percent based on the molecular weight of the copolymer and component (B) is present in the copolymer in an amount of from 1 to 99, preferably 10 to 50 mole percent based on the weight of the copolymer. It has been found that the copolymer compositions thus prepared have a substantially increased boiling water shrinkage and show a great decrease in their tendency to fiatspot when they are used as reinforcing fibers for vehicle tires.

The phenylindan carboxylic acids which are employed in the preparation of the copolymers of the present invention may be represented by the formula:

wherein R is as defined above. Typical suitable compounds falling within this formula are: 3-(4-carboxyphenyl) indan carboxylic acid; 3 (3 carboxyphenyl) 5 indan carboxylic acid; 3 (4 carboxyphenyl) 1,1,3 trimethyl 5 indan carboxylic acid;

3 (3 carboxyphenyl) 1,1,3 triethyl 6 indan carboxylic acid; 3 (4 carboxyphenyl) l methyl 1,3- dipropyl 5 indan earboxylic acid; 3 (4 carboxyphenyl) 1 methyl 1,3 diethyl 6 indan carboxylic acid, and the like. The preferred phenylindan dicarboxylic acid for the preparation of the copolyamides of this invention is 3 (4 earboxyphenyl) 1,1,3 trimethyl 5 indan carboxylic acid which is represented by the formula:

(I) CH3 1104' L C-OII In order to illustrate the invention and the advantages thereof with greater particularity, the following specific examples are given. It is to be understood that they are intended to be only illustrative and not limitative. Parts are given by weight unless otherwise indicated.

Example I A solution containing 125.8 parts (90 mole percent) of hexamethylenediammonium adipate and 23.45 parts (10 mole percent) of the hexamethylenediamine salt of 3-(4- carboxyphenyl) 1,1,3 trimethyl 5 indan carboxylic acid, dissolved in 80 parts of water, was placed in a stainless-steel, high pressure autoclave which had been previously purged with purified nitrogen. The temperature and pressure within the autoclave were slowly raised until values of 220 C. and 250 p.s.i.g., respectively, were reached. The temperature was then further increased to 243 C. while the pressure was maintained at 250 p.s.i.g. by removal of steam as condensate. When this point was reached, the pressure within the autoclave was gradually reduced to atmospheric over a -minute period. During this period the temperature was allowed to level out at 280 C. at which point the polymer melt was allowed to equilibrate for minutes.

The resultant polymer, thus obtained, was nearly transparent and had a melting point of approximately 247 C. This molten polymer was melt spun directly from the bottom of the autoclave through a single-hole spinneret to yield a mono-filament yarn having good textile properties.

Example 11 A solution of 104.2 parts (80 mole percent) of hexamethylenediammonium adipate and 43.9 parts (20 mole percent) of the hexamethylenediamine salt of 3-(4-carboxyphenyl)-l,1,3-trimethyl-5-indan carboxylic acid, dissolved in 80 parts of water, was added to a stainless-steel high-pressure autoclave. Polymerization of this mixture was brought about by the steps and procedures as set forth in Example I. The resulting, transparent polymer melting point was measured to be approximately 236 C.

This finished polymer was melt spun directly from the autoclave through a single-hole spinneret to yield a monofilainent yarn having good textile properties.

Example III A solution of 81.5 parts mole percent) of hexamethylenediammonium adipate and 61.6 parts (30 mole percent) of the hexamethylenediamine salt of 3-(4-carboxyphenyD-l,1,3-trirnethyl-5-indan carboxylic acid, dissolved in parts of water, was added to a stainless-steel high-pressure autoclave. The solution was polymerized in accordance with the conditions and procedures as set forth in Example I. The transparent polymer thus obtained had a melting point of about 222 C. This finished polymer was melt extruded directly from the bottom of the autoclave through a single-hole spinneret yielding a mono-filament yarn of good textile properties.

Example IV A solution was prepared by introducing a mixture of 36.7 parts of hexamethylene diamine and 49.9 parts adipic acid (70 mole percent) and a mixture of 20.8 parts of cyclohexanbis-(methylamine) and 47.5 parts of 3-(4- carboxyphenyl)-1,1,3-trimethyl-5-indan carboxylic acid (30 mole percent) into 80 parts of water. This solution was added to a stainless-steel high pressure autoclave and polymerization was carried out as in Example I. The resulting transparent polymer had a melting point of 229 C. and was spun into a mono-filament yarn having good textile properties.

Comparative tests were conducted to determine relative boiling water shrinkage in comparison to a conventional polyhexamethylene adipamide (nylon 66) yarn. The yarns were exposed to boiling water for a period of 5 minutes and their lengths were measured both before and after exposure. The percent boiling water shrinkage is determined by the following formula:

length before exposurelength after exposure length before exposure l00==pereent boiling Water shrinkage The results obtained in this test are illustrated by the following table:

As can be seen from the above table, the yarns prepared from the copolyamides obtained in accordance with the present invention exhibit a significant increase in boiling water shrinkage when compared to a yarn prepared from a conventional polyamide.

Yarns made from the copolyamides of the present invention were formed into cords and used to reinforce rubber vehicle tires. The tires thus formed were tested for fiatspot severity and were found to have a significant reduction in the amount of fiatspot when compared to conventional polyhexaniethylene adipamide reinforced tires. This reduction in fiatspot was maintained over a variety of conditions of temperature and humidity, thus eliminating the need for any additional additive to counteract the effect of atmospheric changes.

As many widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not to be limited by the specific embodiments set forth herein but only by the claims which follow.

I claim:

1. A linear fiber-forming copolyamide composed of (A) 1 to 99 mole percent based on the molecular weight of the copolyamide of units represented by the structure H HO 0 III I] and (B) 1 to 99 mole percent based .on the molecular weight of the copolyamide of units represented by the structure wherein R is a divalent hydrocarbon radical selected from the group consisting of tetramethylene and 1,4-cyclohexylene and R is a member of the group consisting of hydrogen and alkyl groups containing 1-3 carbon atoms.

2. The linear fiber-forming copolyamide as defined in claim 1 wherein R is methyl.

3. The linear fiber-forming copolyamide as defined in claim 1 wherein R is tetramethylene.

4. The linear fiber-forming copolyamide as described in claim 1 wherein R is 1,4-cyclohexylene.

5. The linear fiber-forming copolyamide as defined in claim 1 wherein R is tetramethylene and R is methyl.

6. A linear fiber-forming copolyamide composed of (A) 90 to 50 mole percent, based on the molecular weight of the copolyamide of units represented by the structure weight of the copolyamide of units represented by the structure wherein R is a divalent hydrocarbon radical selected from the group consisting of tetramethylene and 1,4-cyclohexylene and R is a member of the group consisting of hydrogen and alkyl groups containing 1 to 3 carbon atoms. 7. The linear fiber-forming copolyamide as defined in claim 6 wherein R is tetramethylene and R is methyl. 8. The linear fiber-forming copolyamide as defined in claim 6 wherein R is 1,4-cyclohexylene and R is methyl.

9. A textile fiber composed of the copolyamide as defined in claim 1.

10. A textile fiber composed of the copolyamide as defined in claim 6.

References Cited UNITED STATES PATENTS 2,913,433 11/1959 Wittbecker 260--78 2,918,454 12/ 1959 Graham 26078 3,145,193 8/1964 Gabler 260-78 WILLIAM H. SHORT, Primary Examiner.

H. D. ANDERSON, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,383,368 May 14, 1968 James S. Ridgway I It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, lines 7 to 12, the formula should appear as shown below:

i -N-CH R-CH Signed and sealed this 21st day of October 1969.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR.

Attesting Officer Commissioner of Patents 

